//
//  WBNewFeatureView.swift
//  Swift微博
//
//  Created by WangDaqiang on 2018/8/9.
//  Copyright © 2018年 汪大强. All rights reserved.
//

import UIKit

/// 新特性视图
class WBNewFeatureView: UIView {

    @IBOutlet weak var scrollView: UIScrollView!
    @IBOutlet weak var enterButton: UIButton!
    @IBOutlet weak var pageControl: UIPageControl!
    
    /// 进入微博
    @IBAction func enterStatus(_ sender: Any) {
        removeFromSuperview()
    }
    
    class func newFeatureView() -> WBNewFeatureView {
        let nib = UINib(nibName: "WBNewFeatureView", bundle: nil)
        
        let v = nib.instantiate(withOwner: nil, options: nil)[0] as! WBNewFeatureView
        
        // 从 XIB 加载的视图默认是 600 * 600
        v.frame = UIScreen.main.bounds
        
        return v
    }
    
    override func awakeFromNib() {
        print(bounds)
        // 如果使用自动布局设置的界面，从 XIB 加载默认是 600 * 600 大小
        let count = 4
        let rect = UIScreen.main.bounds
        for i in 0..<count {
            
            let imageName = "new_feature_\(i+1)"
            let iv = UIImageView(image: UIImage(named: imageName))
            
            // 设置大小
            iv.frame = rect.offsetBy(dx: CGFloat(i) * rect.width, dy: 0)
            
            scrollView.addSubview(iv)
        }
        
        // 指定 scrollview 的属性
        scrollView.contentSize = CGSize(width: CGFloat(count + 1) * rect.width, height: rect.height)
        scrollView.bounces = false
        scrollView.isPagingEnabled = true
        scrollView.showsHorizontalScrollIndicator = false
        
        // 隐藏按钮
        enterButton.isHidden = true
        
        scrollView.delegate = self
    }

}

extension WBNewFeatureView: UIScrollViewDelegate {
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        // 1. 滚动到最后一屏
        let page = Int(scrollView.contentOffset.x / scrollView.bounds.width)
        print(page)
        
        // 2. 判断是否最后一页
        if page == scrollView.subviews.count - 1 {
            print("欢迎回来")
            removeFromSuperview()
        }
        
        // 3. 如果是倒数第二页，显示按钮
        enterButton.isHidden = (page != scrollView.subviews.count - 2)
    }
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        // 0. 一旦滚动隐藏按钮
        enterButton.isHidden = true
        
        // 1. 计算当前的偏移量
        let page =  Int(scrollView.contentOffset.x / scrollView.bounds.width + 0.5)
        
        // 2. 设置分页控件
        pageControl.currentPage = page
        
        // 3. 分页控件隐藏
        pageControl.isHidden = (page == scrollView.subviews.count - 1)
    }
}
